High-speed chemical analysis, including hyperspectral imaging and monitoring of dynamic chemical processes, requires collecting and analyzing hyperspectral data. Collecting such data can be very time-consuming. For example, rapid identification and quantification of chemical species in complex mixtures is of importance to a wide range of applications in biology, medicine, manufacturing, and security. Multivariate statistical techniques combined with optical spectroscopies are increasingly employed in such applications for chemical component classification, calibration, and hyperspectral imaging.
Previous schemes have incorporated chemometric techniques into the measurement process by using either static optical interference filters, or tunable liquid crystal or micromirror-based multivariate optical elements built into the spectrometer hardware.
For example, conventional optical array (e.g. charge-coupled device or “CCD”) based spectrometers disperse light of different wavelengths onto N separate detectors in order to measure a spectrum. These devices have drawbacks in the low-signal regime. For example, assuming that a given chemical species emits over a fixed time period ˜100 photons distributed over ˜100 CCD pixels, then the resulting signal at each pixel would be well below the typical CCD read noise of a few counts per pixel.
There is a need, therefore, for optical measurement devices that can operate at low signal levels.
Reference is made to U.S. Pat. No. 6,529,276, U.S. Pat. No. 8,406,859 and US 2007/0177240, each of which is incorporated herein by reference.
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